Synthesis and properties of aromatic polyamides derived from 2,7‐bis(4‐aminophenoxy)napthalene and aromatic dicarboxylic acids

Abstract

Abstract 2,7‐Bis(4‐aminophenoxy)naphthalene, a new polymer‐forming diamine, was synthesized in two steps by the preparation of 2,7‐bis(4‐nitrophenoxy)naphthalene from 2,7‐dihydroxynaphthalene and p ‐chloronitrobenzene and subsequent reduction with a 10% Pd‐C catalys and hydrazine hydrate. Aromatic polyamides and copolyamides having an inherent viscosity in the range of 0,76–1,16 dL/g were prepared by the direct polycondensation of the diamine with various aromatic dicarboxylic acids or with mixed dicarboxylic acids in 1‐methyl‐2‐pyrrolidone (NMP) using triphenyl phosphite and pyridine as condensing agents. Most of the polymers were soluble in aprotic solvents such as NMP and N,N ‐dimethylacetamide (DMAc), and afforded transparent, flexible and tough films upon casting from DMAc solutions. Glass transition temperatures of the polymers were in the range of 246–327°C, and 10% weight loss temperatures were above 501°C in nitrogen and 476°C in air, respectively.